- For the 1986 movie, see the Manhattan Project (film).
The Manhattan Project is the name colloquially used to refer to the effort during World War II to develop the first nuclear weapons of the United States in collaboration with the United Kingdom and Canada, and other European physicists. Formally it refers to the period of the project from 1942-1946 which was under the control of the U.S. Army Corps of Engineers under the administration of General Leslies R. Groves, with its scientific research directed by the American physicist J. Robert Oppenheimer, as the Manhattan Engineering District (MED).
The project succeeded in developing and detonating three nuclear weapons in 1945: a test detonation on July 16 (the Trinity test) near Alamogordo, New Mexico; an enriched uranium bomb code-named "Little Boy" detonated on August 6 over Hiroshima, Japan; and a plutonium bomb code-named "Fat Man" on August 9 over Nagasaki, Japan.
The project's origins were in fears during the 1930s that Nazi Germany was also investigating such weapons of its own. Borne out of a small research program which began in 1939, the Manhattan Project would eventually employ over 130,000 people and cost a total of nearly $2 billion USD ($20 billion in 2004 dollars based on CPI), and resulted in the creation of multiple production and research sites operated in secret.[1]
The three primary research and production sites of the project were the plutonium-production facility at what is now Hanford Site, the uranium-enrichment facilities at what is now Oak Ridge National Laboratory, and the weapons research and design laboratory which is now Los Alamos National Laboratory. Project research took place at over thirty different sites spread across the United States, Canada, and in the United Kingdom. The MED maintained control over U.S. weapons production until the formation of the Atomic Energy Commission in January 1947.
The discovery of nuclear fission
In
nuclear fission, the nucleus of a fissile atom (in this case,
enriched uranium) absorbs a thermal neutron, becomes unstable, and splits into two new atoms, releasing some energy and between one and three new neutrons, which can perpetuate the process.
- Main articles: History of physics, History of nuclear weapons, World War II.
In the first decades of the twentieth century, numerous changes in the understanding of physics occurred which resulted both in the recognition of nuclear fission as a potential energy source and the belief by many that it could be used for a weapon. Chief among these developments were the discovery of a nuclear model of the atom, which by 1932 was thought to consist of a small, dense nucleus containing most of the mass of the atom in the form of protons and neutrons, surrounded by a shell of electrons. Work on the phenomena of radioactivity, first discovered in uranium ores by Henri Becquerel in 1896 and followed up by the work of Pierre and Marie Curie on radium, seemed to promise that atoms, previously thought to be ultimately stable and indivisible, actually had the potential of containing and release immense amounts of energy.
The road towards nuclear fission accelerated in the 1930s. In 1932, John Cockcroft and Ernest Walton first "split the atom", transmutating a and in 1934, Irène and Frédéric Joliot-Curie discovered that artificial radioactivity could be induced in stable elements by bombarding them with alpha particles. The same year Enrico Fermi reported similar results when bombarding uranium with neutrons, but he did not immediately appreciate the consequences of his results.
Fascism began to take over Europe at the same time as discoveries were being made about the use of nuclear energy for war.
In December 1938, Germans Otto Hahn and Fritz Strassman published experimental results about the bombardment of uranium with neutrons, showing that it somehow produced an isotope of barium as a result. Collaborator Lise Meitner (a political refugee in Sweden at the time) and Otto Robert Frisch correctly interpreted the results as the splitting of the uranium nucleus after the absorption of a neutron—nuclear fission—which released a large amount of energy and additional neutrons. In 1933 Hungarian physicist Leó Szilárd had proposed that if a neutron-driven process released more neutrons than those required to start it, an expanding nuclear chain reaction might result. Upon experimentation, he found that the fission of uranium indeed released two or more neutrons on average, though he kept this secret for the time being, fearing its use as a weapon by fascist governments. Identical results were soon published by the Joliot-Curie group, however, to the dismay of Szilárd.
That such mechanisms might have implications for civilian power or military weapons was perceived by a number of scientists in many different countries around the same time. While all of these developments in science were occurring, however, many great political changes were happening in Europe. Adolf Hitler was appointed chancellor of Germany in January 1933. His anti-Semitic ideology caused all Jewish civil servants, which included many physicists at universities, to be fired from their posts. Consequently many European physicists who would later make key discoveries went into exile in the United Kingdom and the United States. After Nazi Germany invaded Poland in 1939, World War II began, and many scientists in the United States and Great Britain became anxious about what Germany might do with nuclear technology.
Early U.S. and UK research
- Main articles: S-1 Uranium Committee, MAUD Committee, National Defense Research Committee
The idea that nuclear fission could be used for both the production of commercial energy as well as potentially for military purposes occurred to many scientists around the world nearly simultaneously. Because of the escalating military conflict in Europe, many scientists discontinued publication on the subject for fear of aiding enemy scientists with their research. The primary difficulty, it was soon determined by Niels Bohr and John Wheeler: only one isotope of uranium, uranium-235 underwent fission, and it composed less than 1% of all uranium found in nature. The majority of uranium is uranium-238, the presence of which would actually inhibit a fission chain reaction. To make a uranium fission bomb would require the separation of the two almost identical atoms with a relatively high degree of accuracy — a massive amount of effort, depending on how much uranium-235 (enriched uranium) was needed for a bomb, which had not yet been determined.
In the United States, a group of three Hungarian Jewish refugee physicists, Leó Szilárd, Edward Teller, and Eugene Wigner believed that the energy released in nuclear fission might be used in bombs by the Germans — who had made many early discoveries in the physics of fission and still had a number of formidable physicists, including Werner Heisenberg, despite the expulsion of Jewish academics — and were desperate to encourage further research in the United States. Politically marginalized, however, they sought the assistance of Albert Einstein, easily the world's most famous physicist at the time and a Jewish refugee himself, in drafting a letter which they would attempt to have delivered to President Franklin D. Roosevelt. The Einstein-Szilárd letter was written on August 2, 1939, mostly by Szilárd, and warned that "extremely powerful bombs of a new type may thus be constructed" by means of nuclear fission, urging President to establish funds for further research in the U.S. to determine its feasibility.
The letter eventually made it to Roosevelt over a month later, who authorized the reaction of an ad hoc Uranium Committee under the chairmanship of National Bureau of Standards chief Lyman Briggs. It began small research programs in 1939 at the Naval Research Laboratory in Washington, where physicist Philip Abelson explored uranium isotope separation. At Columbia University Enrico Fermi, who had emigrated because his wife was Jewish, built prototype nuclear reactors using various configurations of graphite and uranium. Work, however, proceeded at a relatively slow and uncoordinated pace, in part because the U.S. was not yet involved officially in World War II, and because Briggs was uncomfortable in pursuing research at a full pace. In 1940, the Uranium Committee became a section of the newly-established National Defense Research Committee, run by the scientist-administrator Vannevar Bush, but was still a relatively small effort.
One of the early sections of a
particle accelerator responsible for development of the
atomic bomb, and used to assist in research related to the Manhattan Project.
While the U.S. research was pursued at a leisurely pace, work in the United Kingdom was occurring as well. In March 1940 in Birmingham UK, two more German emigrés, Otto Frisch and Rudolf Peierls calculated that an atomic weapon only needed a few pounds of uranium-235, a far smaller amount than most scientists had originally expected, which made it seem highly possible that a weapon could be produced in a short amount of time. They sent their report, the Frisch-Peierls memorandum, to Henry Tizard, chairman of the Committee for the Scientific Survey of Air Warfare, the most important scientific committee in the British war effort. Tizard set up a sub-committee, the MAUD Committee, to investigate the feasibility in more depth, and after commissioning further research, the MAUD Committee produced their first report in March 1941. The committee confirmed that a uranium bomb could be produced using 25 pounds of uranium-235, and would produce an explosion equivalent to that of 1,800 tons of TNT. The research had also shown that isotopic separation of the required quantity of uranium-235 was technically feasible.
Meanwhile in the U.S., the Uranium Committee had not made comparable progress. The first MAUD Report was sent from Britain to the USA in March 1941 but no comment was received from the USA. A member of the MAUD Committee and Frisch's and Peierl's professor, Mark Oliphant, flew to the US in August 1941 in a bomber to find out what was being done with the MAUD reports, and was horrified to discover that Lyman Briggs had simply locked them in his safe, telling nobody, not even the other members of the Uranium Committee, which had since become part of the Office of Scientific Research and Development in the summer of 1941, because the US was "not at war". There was little urgency elsewhere until Oliphant visited Ernest Lawrence, James Conant, chairman of the NDRC, and Enrico Fermi and told them of the MAUD Report. Lawrence also contacted Conant and Arthur Compton, a physicist and Nobel laureate at the University of Chicago, convincing them that they should take Frisch's and Peierl's work very seriously, and collectively, along with Vannevar Bush, an aggressive campaign was made to wrest the weapons research out of the hands of Briggs and to encourage an all-out program.
The National Academy of Sciences then proposed an all-out effort to build nuclear weapons. On October 9, 1941, Bush impressed upon Roosevelt at a meeting the need for an accelerated program, and by November Roosevelt had authorized an "all-out" effort. A new policy committee, the Top Policy Group, was created to inform Roosevelt of bomb development, and allow Bush and his colleagues to guide the project. The first meeting of the group, which discussed the reorganization of the S-1 committee research, took place on December 7, 1941 — the day before the Japanese attack on Pearl Harbor and the entrance of the United States into World War II.
The program starts in earnest
In December 1941, scientists at the University of Chicago Metallurgical Laboratory, the University of California Radiation Laboratory and Columbia University's physics department, accelerated their efforts to prepare the nuclear materials for a weapon.
Arthur Compton organized the Metallurgical Laboratory at the University of Chicago in early 1942 to study plutonium and fission piles. Compton asked theoretical physicist Dr. J. Robert Oppenheimer of the University of California to take over research on fast neutron calculations, essential to the development of a nuclear weapon. John Manley, a physicist at the University of Chicago Metallurgical Laboratory, was assigned to help Dr. Oppenheimer find answers by coordinating and contacting several experimental physics groups scattered across the country.
Plutonium seemed to provide a better method of making a bomb, but much less was known about it. Two parallel and completely separate efforts were undertaken. One project produced a uranium bomb and the other route produced two plutonium bombs, all of which were successfully detonated in 1945.
The conferences of summer 1942
During the spring of 1942, Oppenheimer and Robert Serber of the University of Illinois, worked on the problems of neutron diffusion (how neutrons moved in the chain reaction) and hydrodynamics (how the explosion produced by the chain reaction might behave). To review this work and the general theory of fission reactions, Oppenheimer convened a summer study at the University of California, Berkeley in June 1942. Theorists Hans Bethe, John Van Vleck, Edward Teller, Felix Bloch, Emil Konopinski, Robert Serber, Stanley S. Frankel, and Eldred C. Nelson (the latter three all former students of Oppenheimer) confirmed that a fission bomb was feasible. The scientists suggested that such a reaction could be initiated by assembling a critical mass - an amount of nuclear explosive adequate to sustain it - either by firing two subcritical masses of plutonium or uranium 235 together or by imploding (crushing) a hollow sphere made of these materials with a blanket of high explosives. (Serber credits an early idea of implosion to Tolman). Until more quantitative data on fission reactions became available, this was all that could be done.
Teller saw another possibility: by surrounding a fission bomb with deuterium and tritium, a much more powerful "superbomb" (which he called simply, the "Super") might be constructed. This concept was based on studies of energy production in stars made by Bethe before the war. When the detonation wave from the fission bomb moved through the mixture of deuterium and tritium nuclei, these would fuse together to produce much more energy than fission could. This process of nuclear fusion is similar to the way that elements fuse in stars to produce light.
Bethe was skeptical. As Teller pushed hard for his "superbomb", proposing scheme after scheme, Bethe refuted each one. The fusion idea had to be put aside while the fission bombs, and the war, were completed. (The "super", or thermonuclear device, was produced after the war and tested in 1952, after an acrimonious political fight pitting Teller against Oppenheimer, leading to loss of Oppenheimer's official status. However the H-bomb used methods different than Teller's, which Bethe had correctly refuted.)
Teller also raised the speculative possibility that an atomic bomb might "ignite" the atmosphere, due to a hypothetical fusion reaction of nitrogen nuclei. Bethe calculated, according to Serber, that it could not happen. In his book The Road from Los Alamos, Bethe says a refutation was written by Konopinski, C. Marvin, and Teller as report LA-602 (declassified Feb. 1973, PDF), showing that ignition of the atmosphere was impossible, not just unlikely. In Serber's account, Oppenheimer unfortunately mentioned it to Arthur Compton, who "didn't have enough sense to shut up about it. It somehow got into a document that went to Washington" which led to the question "never [being] laid to rest". In Bethe's account, this ultimate catastrophe came up again in 1975 when it appeared in a magazine article by H. C. Dudley, who got the idea from a report by Pearl Buck of an interview she had with Arthur Compton in 1959. The worry was not entirely extinguished in some people's minds until the Trinity test.
The conferences in the summer of 1942 provided the detailed theoretical basis for the design of the atomic bomb at Los Alamos. The conclusions were later summarized by Serber in "The Los Alamos Primer" (LA-1, PDF).
Project sites
Though it involved over thirty different research and production sites, the Manhattan Project was largely carried out in three secret scientific cities that were established by power of eminent domain: Hanford, Washington, Los Alamos, New Mexico, and Oak Ridge, Tennessee. The Los Alamos National Laboratory was built on a mesa that previously hosted the Los Alamos Ranch School. The Hanford Site, which grew to almost 1000 square miles (2,600 km²), took over irrigated farm land, fruit orchards, a railroad, and two active farming communities, Hanford and White Bluffs. The Oak Ridge facilities cover more than 60,000 acres (243 km²) of several former farm communities. Some Tennessee families were given two weeks' notice to vacate family farm lands that had been their home for generations. The existence of these sites and the secret cities of Los Alamos, Oak Ridge, and Hanford were officially secret until the end of WWII.
A selection of U.S. sites important to the Manhattan Project.
Major Manhattan Project sites and subdivisions included:
Need for coordination
The measurements of the interactions of fast neutrons with the materials in a bomb were essential because the number of neutrons produced in the fission of uranium and plutonium must be known, and because the substance surrounding the nuclear material must have the ability to reflect, or scatter, neutrons back into the chain reaction before it is blown apart in order to increase the energy produced. Therefore, the neutron scattering properties of materials had to be measured to find the best reflectors.
Estimating the explosive power required knowledge of many other nuclear properties, including the cross section (a measure of the probability of an encounter between particles that result in a specified effect) for nuclear processes of neutrons in uranium and other elements. Fast neutrons could only be produced in particle accelerators, which were still relatively uncommon instruments in physics departments in 1942.
The need for better coordination was clear. By September 1942, the difficulties involved with conducting preliminary studies on nuclear weapons at universities scattered throughout the country indicated the need for a laboratory dedicated solely to that purpose. An even greater need was the construction of massive industrial plants to produce uranium-235 and plutonium - the fissionable materials that would provide the nuclear explosives.
Vannevar Bush, the head of the civilian Office of Scientific Research and Development (OSRD), asked President Roosevelt to assign the large-scale operations connected with the quickly growing nuclear weapons project to the military. Roosevelt chose the Army to work with the OSRD in building production plants. The Army Corps of Engineers selected Col. James Marshall to oversee the construction of factories to separate uranium isotopes and manufacture plutonium for the bomb.
Marshall and his deputy, Col. Kenneth Nichols, had to struggle to understand the various proposed processes and the scientists with whom they had to work. Thrust suddenly into the new field of nuclear physics, they felt unable to distinguish between technical and personal preferences. Although they decided that a site near Knoxville would be suitable for the first production plant, they did not know how large the site had to be and so put off its acquisition. There were other problems, too.
Because of its experimental nature, the nuclear weapons work could not compete with the Army's more-urgent tasks for top-priority ratings. The selection of scientists' work and production-plant construction often were delayed by Marshall's inability to get the critical materials, such as steel, that also were needed in other military productions.
Even selecting a name for the new Army project was difficult. The title chosen by Gen. Brehon Somervell, "Development of Substitute Materials," was objectionable because it seemed to reveal too much.
The Manhattan Engineering District
In the summer of 1942, Col. Leslie Groves was deputy to the chief of construction for the Army Corps of Engineers and had overseen construction of the Pentagon, the world's largest office building. Hoping for an overseas command, Groves vigorously objected when Somervell appointed him to take charge of the weapons project. His objections were overruled and Groves resigned himself to leading a project he thought had little chance of succeeding. Groves appointed Oppenheimer as the project's scientific director, to the surprise of many. (Oppenheimer's radical political views were thought to pose security problems).
The first thing he did was rechristen the project The Manhattan District. The name evolved from the Corps of Engineers practice of naming districts after its headquarters' city (Marshall's headquarters were in New York City). At the same time, Groves was promoted to brigadier general, which gave him the rank thought necessary to deal with the senior scientists in the project.
Within a week of his appointment, Groves had solved the Manhattan Project's most urgent problems. His forceful and effective manner was soon to become all too familiar to the atomic scientists.
The first major scientific hurdle of the project was solved on December 2, 1942 beneath the bleachers of Stagg Field at the University of Chicago, where a team led by Enrico Fermi initiated the first self-sustaining nuclear chain reaction in an experimental reactor named Chicago Pile-1. A coded phone call from Compton saying, "The Italian navigator (referring to Fermi) has landed in the new world, the natives are friendly" to Conant in Washington, DC, brought the news that the experiment was a success. This was a major turning point.
The uranium bomb
The Hiroshima bomb, Little Boy, was made from uranium-235, a rare isotope of uranium that has to be physically separated from more prevalent uranium-238 isotope, which is not suitable for use in an explosive device. However U-235 is only 0.7% of raw uranium and chemically identical to the 99.3% of U-238, so various physical methods were considered for separation.
One method of separating uranium 235 from raw uranium ore was devised by Franz Simon and Nicholas Kurti, two more Jewish emigrés, at Oxford University. Their method using gaseous diffusion was scaled up in large separation plants at Oak Ridge Laboratories. These used uranium hexafluoride (UF6) gas as the process fluid, see gaseous diffusion. This method eventually produced most of the U-235.
Another method - electromagnetic isotope separation, was developed by Ernest Lawrence at the University of California Radiation Laboratory at the University of California, Berkeley. This method resulted in devices known as calutrons which were effectively mass spectrometers. Initially the method seemed promising for large-scale production, but it proved to be expensive and it could not produce enough material. It was later abandoned. Other techniques were also tried, such as thermal diffusion. Most of this separation work was performed at Oak Ridge.
The uranium bomb was a gun-type fission weapon: a critical mass of the U-235 is assembled by firing one mass of U-235, the "bullet," down a more or less conventional gun barrel into another mass of U-235, rapidly creating a critical mass of U-235 which results in a huge explosion.
The plutonium bomb
The basic concept of an implosion-style nuclear weapon.
In contrast, the bombs used in the first test at Trinity Site, New Mexico (the gadget of the Trinity test), and also in the Nagasaki bomb, Fat Man, were made primarily of Plutonium-239. Plutonium is a synthetic element.
Although uranium-238 is useless as fissile material for an atomic bomb, U-238 is used to produce plutonium. The fission of U-235 produces relatively slow neutrons which will be absorbed by U-238, which after a few days of decay, turns into plutonium-239. The production and purification of plutonium used techniques developed in part by Glenn Seaborg while working at Berkeley and Chicago. Beginning in 1943, huge plants were built to produce plutonium at Hanford (Site W) outside of Richland, Washington.
From 1943 − 1944 development efforts were directed to a gun-type fission weapon with plutonium, called "Thin Man". Once this would be achieved, the uranium version "Little Boy" would require a relatively simple adaptation, it was thought.
Initial tests of the properties of plutonium were done using cyclotron-generated plutonium-239, which was very pure but in very small amounts. On April 5, 1944, Emilio Segrè at Los Alamos received the first sample of Hanford-produced plutonium. Within ten days, he discovered a fatal flaw: reactor-bred plutonium was far less pure than cyclotron-produced plutonium, and as a result had a much higher spontaneous fission rate than uranium-235. The implications of this made a "gun" detonation mechanism unsuitable: because of the relatively slow speed of the gun mechanism, a plutonium bomb would "fizzle" (i.e. blow itself apart before it developed a substantial chain reaction).
Therefore in July 1944 the difficult decision was made to cease work on the plutonium gun method; there would be no "Thin Man." The gun method was further developed for uranium only, which as expected, gave few complications. Most efforts were now directed to a different method for plutonium.
Ideas of using alternative detonation schemes had existed for some time at Los Alamos. One of the more innovative had been the idea of "implosion" — a sub-critical sphere of fissile material could, using chemical explosives, be forced to collapse in on itself, creating a very dense critical mass. Initially it had been entertained as a possible, though unlikely method. But after it was discovered that it was the only possible solution for using plutonium in a nuclear weapon, it received the highest project priority. By the end of July 1944, the entire project had been re-organized around solving the implosion problem. It eventually involved using shaped charges with many explosive lenses in order to produce the perfectly-spherical explosive wave needed for proper compression of the plutonium sphere.
Because of the complexity of detonating an implosion-style weapon necessary for the plutonium bomb, it was decided that a test would be required in order to have any confidence that it would work in practice (and not just be a waste of expensive fissile material). After much preparation, the first nuclear test took place on July 16, 1945, near Alamagordo, New Mexico, under the supervision of Grove's deputy Brig. Gen. Thomas Farrell. This test was dubbed by Oppenheimer as "Trinity".
Similar efforts
A similar effort was undertaken in the USSR headed by Igor Kurchatov (with a specific difference in that some of Kurchatov's World War II investigations came secondhand from Manhattan Project countries, thanks to spies, including at least two on the scientific team at Los Alamos, Klaus Fuchs and Theodore Hall, unknown to each other).
After the MAUD Committee's report, the British and Americans exchanged nuclear information, but initally did not pool their efforts. A separate British project, code-named TUBE ALLOYS, was started but did not have American resources. Consequently the British bargaining position worsened and their motives were mistrusted by the Americans. Collaboration therefore lessened markedly until the Quebec Agreement of August 1943, when a large team of British and Canadian scientists joined the Manhattan Project.
Axis efforts on the bomb has always been an issue of contention, while it is believed that token efforts in Germany, headed by Werner Heisenberg, and in Japan, were also undertaken during the war but made little progress. It was initially feared that Hitler was very close to developing his own bomb. Many Nazi scientists had in fact expressed surprise to their allied captors when the bombs were detonated in Japan; convinced that it was merely propaganda. Incidentally Niels Bohr and Heisenberg discussed the possibility of the atomic bomb prior to and during the war. Bohr had recalled that Heisenberg was unaware that the supercritical mass could be achieved with U-235. In fact, Bohr, Heisenberg and Fermi were all colleagues who were key figures in developing the quantum theory together with Wolfgang Pauli prior to the war.
Together with the cryptographic efforts centered at Bletchley Park and also at Arlington Hall, the development of radar and computers in the UK and later in the USA, and the jet engine in the UK and Germany, the Manhattan Project represents one of few massive, secret, and outstandingly successful technological efforts spawned by the conflict of World War II.
See also
Notes
- ↑ Stephen I. Schwartz Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons. Washington, D.C.: Brookings Institution Press, 1998. Manhattan Project expenditures available online at: http://www.brookings.edu/FP/PROJECTS/NUCWCOST/MANHATTN.HTM.
References
- Overall, administrative, and diplomatic histories of the Manhattan Project
- Groves, Leslie. Now it Can be Told: The Story of the Manhattan Project. New York: Harper, 1962. ISBN 0306707381
- Herken, Gregg. Brotherhood of the Bomb : The Tangled Lives and Loyalties of Robert Oppenheimer, Ernest Lawrence, and Edward Teller. New York: Henry Holt and Co., 2002. ISBN 0805065881
- Hewlett, Richard G., and Oscar E. Anderson. The New World, 1939-1946. University Park: Pennsylvania State University Press, 1962.
- Jungk, Robert, Brighter Than a Thousand Suns: A Personal History of the Atomic Scientists, (NY: Harcourt, Brace, 1956, 1958)
- Rhodes, Richard. The Making of the Atomic Bomb. New York: Simon & Schuster, 1986. ISBN 0671441337
- ________. Dark Sun: The Making of the Hydrogen Bomb. New York: Simon & Schuster, 1995. ISBN 068480400X
- Technical histories
- Sherwin, Martin J. A World Destroyed: The Atomic Bomb and the Grand Alliance. New York: Alfred A. Knopf, 1975. ISBN 0394497945
- Groueff, Stephane. Manhattan Project: The Untold Story of the Making of the Atomic Bomb. Boston: Little, Brown & Co, 1967.
- Hoddeson, Lillian, Paul W. Henriksen, Roger A. Meade, and Catherine L. Westfall. Critical Assembly: A Technical History of Los Alamos During the Oppenheimer Years, 1943-1945. New York: Cambridge University Press, 1993. ISBN 0521441323
- Serber, Robert. The Los Alamos Primer: The First Lectures on How to Build an Atomic Bomb. Berkeley: University of California Press, 1992. ISBN 0520075765 — Original 1943, Los Alamos Report "LA-1", declassified in 1965. (Available on Wikimedia Commons).
- Smyth, Henry DeWolf. Atomic Energy for Military Purposes; the Official Report on the Development of the Atomic Bomb under the Auspices of the United States Government, 1940-1945. Princeton: Princeton University Press, 1945. See Smyth Report.
- Participant accounts
- Badash, Lawrence, Joseph O. Hirschfelder, Herbert P. Broida, eds. Reminiscences of Los Alamos, 1943-1945. Dordrecht, Boston: D. Reidel, 1980. ISBN 902771097X
- Bethe, Hans A. The Road from Los Alamos. New York: Simon and Schuster, 1991. ISBN 0671740121
- Nichols, Kenneth David. The Road to Trinity: A Personal Account of How America's Nuclear Policies Were Made. New York: William Morrow and Company Inc, 1987. ISBN 068806910X
- Serber, Robert. Peace and War: Reminiscences of a Life on the Frontiers of Science. New York: Columbia University Press, 1998. ISBN 0231105460
External links
